Ferrando (bass), captain of the bodyguard of Count Di Luna (baritone), tells his men the story that the brother of the current count was bewitched by a gypsy. She was arrested and put on the stake. Her daughter then kidnapped the little brother, and the next day found in the remains of the stake the charred body of a child.
In the garden of the Prince of Aragon’s castle, Leonora (soprano, lady’s princess) tells her confidant Inez (mezzosoprano) about her love for Manrico (tenor), a troubadour. Inez has strange forebodings here she refuses to follow Leonora’s advice to end this relationship.
Count Di Luna has approached unnoticed to see Leonora, the woman he loves incredibly. Then in the distance the voice of the troubadour sounds, and Luna’s jealousy blazes high. Leonora runs out into the arms of Luna, whose darkness she thinks is Manrico. Manrico, who witnesses this, thinks that Leonora has become unfaithful to him, but she knows how to convince him that it was a mistake, and that she loves him only, and not Luna. This becomes furious and both men decide to play a duel. They rush away and leave Leonora in impotence.
In the gypsy camp the wounded Manrico is being looked after by his mother Azucena (mezzo soprano). He says that he had been able to kill the count, but it was as if a voice from heaven sounded that prevented him from bringing the deadly blow. Azucena does not like it, and in a kind of trance she tells how her mother died at the stake, after she had shouted to her daughter to avenge her. Azucena kidnapped the count’s brother and in a delirium she threw a child into the flames. When the delirium dawned, she realized that she had thrown her own child into the flames instead of the count’s brother. Manrico is appalled by this story, and asks her who he is. Azucena continues to insist that he is her son. Then Ruiz (tenor) comes with the news that Leonora, convinced of the fact that Manrico is dead, wants to go to the monastery. Manrico rushes away to stop her, and Azucena tries, desperately but in vain, to stop him. Leonora is getting ready to enter the monastery, but is stopped by Luna, who wants to kidnap her by force. He is, however, stopped by Manrico and his men.
Azucena, in search of her son, is arrested by the men of Luna and taken to the count. He hears her and his suspicion has been awakened by her story. Ferrando also recognizes her as the gipsy who was also involved in the kidnapping and murder of the count’s brother, and when it turns out she is also Manrico’s mother, the count can not get his luck.
Manrico is about to marry Leonora, but when he hears that Azucena is trapped, he hastens to save her. Manrico is imprisoned and is now in the dungeons of the castle. Leonora has secretly come to the castle to liberate him. She hears him lamenting from the tower in which he is locked up, while the monks in the chapel sing the Miserere. Then Luna comes out and Leonora makes herself known. She begs the count to let her lover go; in return, she will give herself to the count. The count agrees and orders the troubadour to be released. Leonora, who does not intend to give himself to the count, takes poison. In the dungeon Manrico tries to comfort his mother, but in her delusion she tries to warm herself to the flames of the stake that awaits her. Then Leonora enters the dungeon where Manrico sits, and tells him that he is free. He guessed what price she paid for it and cursed her. Then the poison begins to work and she dies in his arms. Luna realizes that he has been deceived and immediately ordered Manrico’s execution. Azucena awakens and tries to stop him, but outside the executioner is already aware of Manrico’s severed head. She screams Luna that he killed his own brother, and after she proclaimed that her mother is now avenged, she collapses dying. The count remains stunned behind.